Stock-Based Compensation Plans and Arrangements - Restricted Stock and Performance Stock Unit Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted Average Grant Date Fair Value
Unrecognized compensation cost	$ 13
Weighted average period for total unrecognized compensation cost	1 year 4 months 24 days
Restricted Stock
Number of Shares
Beginning balance (in shares)	84,392
Granted (in shares)	118,789
Vested and converted to common stock (in shares)	(84,392)
Canceled (in shares)	0
Ending balance (in shares)	118,789	84,392
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 11.73
Granted (in dollars per share)	9.26
Vested (in dollars per share)	11.73
Canceled (in dollars per share)	0
Ending balance (in dollars per share)	$ 9.26	$ 11.73
Fair value of shares vested	$ 1	$ 1	$ 1
Unrecognized compensation cost	$ 1
Weighted average period for total unrecognized compensation cost	6 months
Restricted Stock Units And Performance Stock Units
Number of Shares
Beginning balance (in shares)	5,338,034
Granted (in shares)	3,008,102
Vested and converted to common stock (in shares)	(3,030,536)
Canceled (in shares)	(136,383)
Ending balance (in shares)	5,179,217	5,338,034
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 10.11
Granted (in dollars per share)	10.84
Vested (in dollars per share)	8.78
Canceled (in dollars per share)	11.09
Ending balance (in dollars per share)	$ 11.28	$ 10.11
Fair value of restricted stock units that vested and converted to common stock	$ 27	$ 25	$ 29
Unrecognized compensation cost	$ 12
Weighted average period for total unrecognized compensation cost	1 year 4 months 24 days

Total fair value of restricted stock units that vested and converted to common stock.

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- Definition

Share based compensation arrangement by share based payment award equity instruments other than options canceled forfeited in period weighted average grant date fair value.

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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